Network Working Group                                          E. Decker
Request for Comments: 1493                           cisco Systems, Inc.
Obsoletes: 1286                                              P. Langille
                                          Digital Equipment Corporation
                                                         A. Rijsinghani
                                          Digital Equipment Corporation
                                                          K. McCloghrie
                                               Hughes LAN Systems, Inc.
                                                              July 1993


                    Definitions of Managed Objects
                             for Bridges

Status of this Memo


  This RFC specifies an IAB standards track protocol for the Internet
  community, and requests discussion and suggestions for improvements.
  Please refer to the current edition of the "IAB Official Protocol
  Standards" for the standardization state and status of this protocol.
  Distribution of this memo is unlimited.

Abstract

  This memo defines a portion of the Management Information Base (MIB)
  for use with network management protocols in TCP/IP based internets.
  In particular it defines objects for managing MAC bridges based on
  the IEEE 802.1D-1990 standard between Local Area Network (LAN)
  segments.  Provisions are made for support of transparent bridging.
  Provisions are also made so that these objects apply to bridges
  connected by subnetworks other than LAN segments.

Table of Contents

  1. The Network Management Framework ......................    2
  2. Objects ...............................................    2
  2.1 Format of Definitions ................................    3
  3. Overview ..............................................    3
  3.1 Structure of MIB .....................................    3
  3.1.1 The dot1dBase Group ................................    6
  3.1.2 The dot1dStp Group .................................    6
  3.1.3 The dot1dSr Group ..................................    6
  3.1.4 The dot1dTp Group ..................................    6
  3.1.5 The dot1dStatic Group ..............................    6
  3.2 Relationship to Other MIBs ...........................    6
  3.2.1 Relationship to the 'system' group .................    6
  3.2.2 Relationship to the 'interfaces' group .............    7



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RFC 1493                       Bridge MIB                      July 1993


  3.3 Textual Conventions ..................................    8
  4. Changes from RFC 1286 .................................    8
  5. Definitions ...........................................    9
  5.1 Groups in the Bridge MIB .............................   11
  5.2 The dot1dBase Group Definitions ......................   11
  5.3 The dot1dStp Group Definitions .......................   14
  5.4 The dot1dTp Group Definitions ........................   22
  5.5 The dot1dStatic Group Definitions ....................   28
  5.6 Traps for use by Bridges .............................   31
  6. Acknowledgments .......................................   31
  7. References ............................................   33
  8. Security Considerations ...............................   33
  9. Authors' Addresses ....................................   34

1.  The Network Management Framework

  The Internet-standard Network Management Framework consists of three
  components.  They are:

     STD16/RFC 1155 which defines the SMI, the mechanisms used for
     describing and naming objects for the purpose of management.
     STD16/RFC 1212 defines a more concise description mechanism, which
     is wholly consistent with the SMI.

     RFC 1156 which defines MIB-I, the core set of managed objects for
     the Internet suite of protocols.  STD17/RFC 1213, defines MIB-II,
     an evolution of MIB-I based on implementation experience and new
     operational requirements.

     STD15/RFC 1157 which defines the SNMP, the protocol used for
     network access to managed objects.

  The Framework permits new objects to be defined for the purpose of
  experimentation and evaluation.

2.  Objects

  Managed objects are accessed via a virtual information store, termed
  the Management Information Base or MIB.  Objects in the MIB are
  defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
  defined in the SMI.  In particular, each object is named by an OBJECT
  IDENTIFIER, an administratively assigned name, which specifies an
  object type.  The object type together with an object instance serves
  to uniquely identify a specific instantiation of the object.  For
  human convenience, we often use a textual string, termed the
  descriptor, to also refer to the object type.





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RFC 1493                       Bridge MIB                      July 1993


2.1.  Format of Definitions

  Section 5 contains the specification of all object types contained in
  this MIB module.  The object types are defined using the conventions
  defined in the SMI, as amended by the extensions specified in [9,10].

3.  Overview

  A common device present in many networks is the Bridge.  This device
  is used to connect Local Area Network segments below the network
  layer.

  There are two major modes defined for this bridging; transparent and
  source route.  The transparent method of bridging is defined in the
  draft IEEE 802.1d specification [11].  This memo defines those
  objects needed for the management of a bridging entity operating in
  the transparent mode, as well as some objects applicable to all types
  of bridges.

  To be consistent with IAB directives and good engineering practice,
  an explicit attempt was made to keep this MIB as simple as possible.
  This was accomplished by applying the following criteria to objects
  proposed for inclusion:

         (1)  Start with a small set of essential objects and add only
              as further objects are needed.

         (2)  Require objects be essential for either fault or
              configuration management.

         (3)  Consider evidence of current use and/or utility.

         (4)  Limit the total of objects.

         (5)  Exclude objects which are simply derivable from others in
              this or other MIBs.

         (6)  Avoid causing critical sections to be heavily
              instrumented.  The guideline that was followed is one
              counter per critical section per layer.

3.1.  Structure of MIB

  Objects in this MIB are arranged into groups.  Each group is
  organized as a set of related objects.  The overall structure and
  assignment of objects to their groups is shown below.  Where
  appropriate the corresponding IEEE 802.1d [11] management object name
  is also included.



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RFC 1493                       Bridge MIB                      July 1993


         Bridge MIB Name                  IEEE 802.1d Name

         dot1dBridge
           dot1dBase
             BridgeAddress                Bridge.BridgeAddress
             NumPorts                     Bridge.NumberOfPorts
             Type
             PortTable
               Port                       BridgePort.PortNumber
               IfIndex
               Circuit
               DelayExceededDiscards        .DiscardTransitDelay
               MtuExceededDiscards          .DiscardOnError
           dot1dStp
             ProtocolSpecification
             Priority                     SpanningTreeProtocol
                                            .BridgePriority
             TimeSinceTopologyChange        .TimeSinceTopologyChange
             TopChanges                     .TopologyChangeCount
             DesignatedRoot                 .DesignatedRoot
             RootCost                       .RootCost
             RootPort                       .RootPort
             MaxAge                         .MaxAge
             HelloTime                      .HelloTime
             HoldTime                       .HoldTime
             ForwardDelay                   .ForwardDelay
             BridgeMaxAge                   .BridgeMaxAge
             BridgeHelloTime                .BridgeHelloTime
             BridgeForwardDelay             .BridgeForwardDelay
             PortTable
               Port                        SpanningTreeProtocolPort
                                             .PortNumber
               Priority                      .PortPriority
               State                         .SpanningTreeState
               Enable
               PathCost                      .PortPathCost
               DesignatedRoot                .DesignatedRoot
               DesignatedCost                .DesignatedCost
               DesignatedBridge              .DesignatedBridge
               DesignatedPort                .DesignatedPort
               ForwardTransitions
           dot1dTp
             LearnedEntryDiscards          BridgeFilter.DatabaseSize
                                             .NumDynamic,NumStatic
             AgingTime                     BridgeFilter.AgingTime
             FdbTable
               Address
               Port



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RFC 1493                       Bridge MIB                      July 1993


               Status
             PortTable
               Port
               MaxInfo
               InFrames                    BridgePort.FramesReceived
               OutFrames                     .ForwardOutbound
               InDiscards                    .DiscardInbound
           dot1dStatic
             StaticTable
               Address
               ReceivePort
               AllowedToGoTo
               Status

  The following IEEE 802.1d management objects have not been included
  in the Bridge MIB for the indicated reasons.

         IEEE 802.1d Object              Disposition

         Bridge.BridgeName               Same as sysDescr (MIB II)
         Bridge.BridgeUpTime             Same as sysUpTime (MIB II)
         Bridge.PortAddresses            Same as ifPhysAddress (MIB II)
         BridgePort.PortName             Same as ifDescr (MIB II)
         BridgePort.PortType             Same as ifType (MIB II)
         BridgePort.RoutingType          Derivable from the implemented
                                         groups

         SpanningTreeProtocol
             .BridgeIdentifier           Combination of dot1dStpPriority
                                         and dot1dBaseBridgeAddress
             .TopologyChange             Since this is transitory, it
                                         is not considered useful.
         SpanningTreeProtocolPort
             .Uptime                     Same as ifLastChange (MIB II)
             .PortIdentifier             Combination of dot1dStpPort
                                         and dot1dStpPortPriority
             .TopologyChangeAcknowledged Since this is transitory, it
                                         is not considered useful.
             .DiscardLackOfBuffers       Redundant

         Transmission Priority           These objects are not required
                                         as per the Pics Proforma and
                                         not considered useful.
             .TransmissionPriorityName
             .OutboundUserPriority
             .OutboundAccessPriority





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RFC 1493                       Bridge MIB                      July 1993


3.1.1.  The dot1dBase Group

  This mandatory group contains the objects which are applicable to all
  types of bridges.

3.1.2.  The dot1dStp Group

  This group contains the objects that denote the bridge's state with
  respect to the Spanning Tree Protocol.  If a node does not
  implemented the Spanning Tree Protocol, this group will not be
  implemented.

3.1.3.  The dot1dSr Group

  This group contains the objects that describe the entity's state with
  respect to source route bridging.  If source routing is not supported
  this group will not be implemented.  This group is applicable to
  source route only, and SRT bridges.  This group will be described in
  a separate document applicable only to source route bridging.

3.1.4.  The dot1dTp Group

  This group contains objects that describe the entity's state with
  respect to transparent bridging.  If transparent bridging is not
  supported this group will not be implemented.  This group is
  applicable to transparent only and SRT bridges.

3.1.5.  The dot1dStatic Group

  This group contains objects that describe the entity's state with
  respect to destination-address filtering.  If destination-address
  filtering is not supported this group will not be implemented.  This
  group is applicable to any type of bridge which performs
  destination-address filtering.

3.2.  Relationship to Other MIBs

  As described above, some IEEE 802.1d management objects have not been
  included in this MIB because they overlap with objects in other MIBs
  applicable to a bridge implementing this MIB.  In particular, it is
  assumed that a bridge implementing this MIB will also implement (at
  least) the 'system' group and the 'interfaces' group defined in MIB-
  II [6].

3.2.1.  Relationship to the 'system' group

  In MIB-II, the 'system' group is defined as being mandatory for all
  systems such that each managed entity contains one instance of each



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RFC 1493                       Bridge MIB                      July 1993


  object in the 'system' group.  Thus, those objects apply to the
  entity as a whole irrespective of whether the entity's sole
  functionality is bridging, or whether bridging is only a subset of
  the entity's functionality.

3.2.2.  Relationship to the 'interfaces' group

  In MIB-II, the 'interfaces' group is defined as being mandatory for
  all systems and contains information on an entity's interfaces, where
  each interface is thought of as being attached to a `subnetwork'.
  (Note that this term is not to be confused with `subnet' which refers
  to an addressing partitioning scheme used in the Internet suite of
  protocols.) The term 'segment' is used in this memo to refer to such
  a subnetwork, whether it be an Ethernet segment, a 'ring', a WAN
  link, or even an X.25 virtual circuit.

  Implicit in this Bridge MIB is the notion of ports on a bridge.  Each
  of these ports is associated with one interface of the 'interfaces'
  group, and in most situations, each port is associated with a
  different interface. However, there are situations in which multiple
  ports are associated with the same interface.  An example of such a
  situation would be several ports each corresponding one-to-one with
  several X.25 virtual circuits but all on the same interface.

  Each port is uniquely identified by a port number.  A port number has
  no mandatory relationship to an interface number, but in the simple
  case a port number will have the same value as the corresponding
  interface's interface number.  Port numbers are in the range
  (1..dot1dBaseNumPorts).

  Some entities perform other functionality as well as bridging through
  the sending and receiving of data on their interfaces.  In such
  situations, only a subset of the data sent/received on an interface
  is within the domain of the entity's bridging functionality.  This
  subset is considered to be delineated according to a set of
  protocols, with some protocols being bridged, and other protocols not
  being bridged. For example, in an entity which exclusively performed
  bridging, all protocols would be considered as being bridged, whereas
  in an entity which performed IP routing on IP datagrams and only
  bridged other protocols, only the non-IP data would be considered as
  being bridged.

  Thus, this Bridge MIB (and in particular, its counters) are
  applicable only to that subset of the data on an entity's interfaces
  which is sent/received for a protocol being bridged.  All such data
  is sent/received via the ports of the bridge.





Decker, Langille, Rijsinghani & McCloghrie                      [Page 7]

RFC 1493                       Bridge MIB                      July 1993


3.3.  Textual Conventions

  The datatypes, MacAddress, BridgeId and Timeout, are used as textual
  conventions in this document.  These textual conventions have NO
  effect on either the syntax nor the semantics of any managed object.
  Objects defined using these conventions are always encoded by means
  of the rules that define their primitive type.  Hence, no changes to
  the SMI or the SNMP are necessary to accommodate these textual
  conventions which are adopted merely for the convenience of readers.

4.  Changes from RFC 1286

         (1)  Updated all text to remove references to source route
              bridging where not applicable.  SR MIB will be a separate
              document.

         (2)  Removed dot1dSrPortTable.  Retained OID definition of
              dot1dSr.

         (3)  Updated all references of "draft P802.1d/D9" to "IEEE
              802.1D-1990".

         (4)  Updated bibliography.

         (5)  Added clarification to description of dot1dPortPathCost.

         (6)  Put recommended default in description of
              dot1dStaticAllowedToGoTo.

         (7)  Put recommended default in description of
              dot1dStaticStatus.

         (8)  Put recommended default in description of
              dot1dTpAgingTime.  Specified range of (10..1000000).

         (9)  Updated all port number syntaxes, when used as index, to
              use the range (1..65535).

         (10) Updated definition of dot1dTpPortInFrames and
              dot1dTpPortOutFrames.

         (11) Added text to the traps indicating that they are
              optional.

         (12) Clarified definition of dot1dStpForwardDelay.






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RFC 1493                       Bridge MIB                      July 1993


5.  Definitions

         BRIDGE-MIB DEFINITIONS ::= BEGIN

         IMPORTS
                    Counter, TimeTicks
                            FROM RFC1155-SMI
                    mib-2
                            FROM RFC1213-MIB
                    OBJECT-TYPE
                            FROM RFC-1212
                    TRAP-TYPE
                            FROM RFC-1215;

         -- All representations of MAC addresses in this MIB Module
         -- use, as a textual convention (i.e. this convention does
         -- not affect their encoding), the data type:

         MacAddress ::= OCTET STRING (SIZE (6))    -- a 6 octet address
                                                   -- in the
                                                   -- "canonical"
                                                   -- order
         -- defined by IEEE 802.1a, i.e., as if it were transmitted
         -- least significant bit first, even though 802.5 (in
         -- contrast to other n802.x protocols) requires MAC
         -- addresses to be transmitted most significant bit first.
         --
         -- 16-bit addresses, if needed, are represented by setting
         -- their upper 4 octets to all 0's, i.e., AAFF would be
         -- represented as 00000000AAFF.


         -- Similarly, all representations of Bridge-Id in this MIB
         -- Module use, as a textual convention (i.e. this
         -- convention does not affect their encoding), the data
         -- type:

         BridgeId ::= OCTET STRING (SIZE (8))   -- the
                                                -- Bridge-Identifier
                                                -- as used in the
                                                -- Spanning Tree
         -- Protocol to uniquely identify a bridge.  Its first two
         -- octets (in network byte order) contain a priority
         -- value and its last 6 octets contain the MAC address
         -- used to refer to a bridge in a unique fashion
         -- (typically, the numerically smallest MAC address
         -- of all ports on the bridge).




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         -- Several objects in this MIB module represent values of
         -- timers used by the Spanning Tree Protocol.  In this
         -- MIB, these timers have values in units of hundreths of
         -- a second (i.e. 1/100 secs).
         -- These timers, when stored in a Spanning Tree Protocol's
         -- BPDU, are in units of 1/256 seconds.  Note, however,
         -- that 802.1D-1990 specifies a settable granularity of
         -- no more than 1 second for these timers.  To avoid
         -- ambiguity, a data type is defined here as a textual
         -- convention and all representation of these timers
         -- in this MIB module are defined using this data type.  An
         -- algorithm is also defined for converting between the
         -- different units, to ensure a timer's value is not
         -- distorted by multiple conversions.
         -- The data type is:

         Timeout ::= INTEGER -- a STP timer in units of 1/100 seconds

         -- To convert a Timeout value into a value in units of
         -- 1/256 seconds, the following algorithm should be used:
         --
         --      b  = floor( (n * 256) / 100)
         --
         -- where:
         --      floor   =  quotient [ignore remainder]
         --      n is the value in 1/100 second units
         --      b is the value in 1/256 second units
         --
         -- To convert the value from 1/256 second units back to
         -- 1/100 seconds, the following algorithm should be used:
         --
         --      n = ceiling( (b * 100) / 256)
         --
         -- where:
         --      ceiling =  quotient [if remainder is 0], or
         --                 quotient + 1 [if remainder is non-zero]
         --      n is the value in 1/100 second units
         --      b is the value in 1/256 second units
         --
         -- Note: it is important that the arithmetic operations are
         -- done in the order specified (i.e., multiply first, divide
         -- second).


            dot1dBridge   OBJECT IDENTIFIER ::= { mib-2 17 }






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RFC 1493                       Bridge MIB                      July 1993


         -- groups in the Bridge MIB

         dot1dBase     OBJECT IDENTIFIER ::= { dot1dBridge 1 }

         dot1dStp      OBJECT IDENTIFIER ::= { dot1dBridge 2 }

         dot1dSr       OBJECT IDENTIFIER ::= { dot1dBridge 3 }
         -- separately documented

         dot1dTp       OBJECT IDENTIFIER ::= { dot1dBridge 4 }

         dot1dStatic   OBJECT IDENTIFIER ::= { dot1dBridge 5 }


         -- the dot1dBase group

         -- Implementation of the dot1dBase group is mandatory for all
         -- bridges.

         dot1dBaseBridgeAddress OBJECT-TYPE
             SYNTAX  MacAddress
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The MAC address used by this bridge when it must
                     be referred to in a unique fashion.   It is
                     recommended that this be the numerically smallest
                     MAC address of all ports that belong to this
                     bridge.  However it is only required to be unique.
                     When concatenated with dot1dStpPriority a unique
                     BridgeIdentifier is formed which is used in the
                     Spanning Tree Protocol."
             REFERENCE
                     "IEEE 802.1D-1990: Sections 6.4.1.1.3 and 3.12.5"
             ::= { dot1dBase 1 }

         dot1dBaseNumPorts OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of ports controlled by this bridging
                     entity."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.4.1.1.3"
             ::= { dot1dBase 2 }

         dot1dBaseType OBJECT-TYPE



Decker, Langille, Rijsinghani & McCloghrie                     [Page 11]

RFC 1493                       Bridge MIB                      July 1993


             SYNTAX  INTEGER {
                         unknown(1),
                         transparent-only(2),
                         sourceroute-only(3),
                         srt(4)
                     }
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "Indicates what type of bridging this bridge can
                     perform.  If a bridge is actually performing a
                     certain type of bridging this will be indicated by
                     entries in the port table for the given type."
             ::= { dot1dBase 3 }

         -- The Generic Bridge Port Table

         dot1dBasePortTable OBJECT-TYPE
             SYNTAX  SEQUENCE OF Dot1dBasePortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A table that contains generic information about
                     every port that is associated with this bridge.
                     Transparent, source-route, and srt ports are
                     included."
             ::= { dot1dBase 4 }

         dot1dBasePortEntry OBJECT-TYPE
             SYNTAX  Dot1dBasePortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A list of information for each port of the
                     bridge."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.4.2, 6.6.1"
             INDEX  { dot1dBasePort }
             ::= { dot1dBasePortTable 1 }


         Dot1dBasePortEntry ::=
             SEQUENCE {
                 dot1dBasePort
                     INTEGER,
                 dot1dBasePortIfIndex
                     INTEGER,
                 dot1dBasePortCircuit



Decker, Langille, Rijsinghani & McCloghrie                     [Page 12]

RFC 1493                       Bridge MIB                      July 1993


                     OBJECT IDENTIFIER,
                 dot1dBasePortDelayExceededDiscards
                     Counter,
                 dot1dBasePortMtuExceededDiscards
                     Counter
             }

         dot1dBasePort OBJECT-TYPE
             SYNTAX  INTEGER (1..65535)
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The port number of the port for which this entry
                     contains bridge management information."
             ::= { dot1dBasePortEntry 1 }

         dot1dBasePortIfIndex OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The value of the instance of the ifIndex object,
                     defined in MIB-II, for the interface corresponding
                     to this port."
             ::= { dot1dBasePortEntry 2 }

         dot1dBasePortCircuit OBJECT-TYPE
             SYNTAX  OBJECT IDENTIFIER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "For a port which (potentially) has the same value
                     of dot1dBasePortIfIndex as another port on the
                     same bridge, this object contains the name of an
                     object instance unique to this port.  For example,
                     in the case where multiple ports correspond one-
                     to-one with multiple X.25 virtual circuits, this
                     value might identify an (e.g., the first) object
                     instance associated with the X.25 virtual circuit
                     corresponding to this port.

                     For a port which has a unique value of
                     dot1dBasePortIfIndex, this object can have the
                     value { 0 0 }."
             ::= { dot1dBasePortEntry 3 }

         dot1dBasePortDelayExceededDiscards OBJECT-TYPE
             SYNTAX  Counter



Decker, Langille, Rijsinghani & McCloghrie                     [Page 13]

RFC 1493                       Bridge MIB                      July 1993


             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of frames discarded by this port due
                     to excessive transit delay through the bridge.  It
                     is incremented by both transparent and source
                     route bridges."
             REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
             ::= { dot1dBasePortEntry 4 }

         dot1dBasePortMtuExceededDiscards OBJECT-TYPE
             SYNTAX  Counter
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of frames discarded by this port due
                     to an excessive size.  It is incremented by both
                     transparent and source route bridges."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.6.1.1.3"
             ::= { dot1dBasePortEntry 5 }


         -- the dot1dStp group

         -- Implementation of the dot1dStp group is optional.  It is
         -- implemented by those bridges that support the Spanning Tree
         -- Protocol.


         dot1dStpProtocolSpecification OBJECT-TYPE
             SYNTAX  INTEGER {
                         unknown(1),
                         decLb100(2),
                         ieee8021d(3)
                     }
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "An indication of what version of the Spanning
                     Tree Protocol is being run.  The value
                     'decLb100(2)' indicates the DEC LANbridge 100
                     Spanning Tree protocol.  IEEE 802.1d
                     implementations will return 'ieee8021d(3)'.  If
                     future versions of the IEEE Spanning Tree Protocol
                     are released that are incompatible with the
                     current version a new value will be defined."



Decker, Langille, Rijsinghani & McCloghrie                     [Page 14]

RFC 1493                       Bridge MIB                      July 1993


             ::= { dot1dStp 1 }

         dot1dStpPriority OBJECT-TYPE
             SYNTAX  INTEGER (0..65535)
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The value of the write-able portion of the Bridge
                     ID, i.e., the first two octets of the (8 octet
                     long) Bridge ID.  The other (last) 6 octets of the
                     Bridge ID are given by the value of
                     dot1dBaseBridgeAddress."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.7"
             ::= { dot1dStp 2 }

         dot1dStpTimeSinceTopologyChange OBJECT-TYPE
             SYNTAX  TimeTicks
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The time (in hundredths of a second) since the
                     last time a topology change was detected by the
                     bridge entity."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.8.1.1.3"
             ::= { dot1dStp 3 }

         dot1dStpTopChanges OBJECT-TYPE
             SYNTAX  Counter
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The total number of topology changes detected by
                     this bridge since the management entity was last
                     reset or initialized."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.8.1.1.3"
             ::= { dot1dStp 4 }

         dot1dStpDesignatedRoot OBJECT-TYPE
             SYNTAX  BridgeId
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The bridge identifier of the root of the spanning
                     tree as determined by the Spanning Tree Protocol
                     as executed by this node.  This value is used as



Decker, Langille, Rijsinghani & McCloghrie                     [Page 15]

RFC 1493                       Bridge MIB                      July 1993


                     the Root Identifier parameter in all Configuration
                     Bridge PDUs originated by this node."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.1"
             ::= { dot1dStp 5 }

         dot1dStpRootCost OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The cost of the path to the root as seen from
                     this bridge."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.2"
             ::= { dot1dStp 6 }

         dot1dStpRootPort OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The port number of the port which offers the
                     lowest cost path from this bridge to the root
                     bridge."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.3"
             ::= { dot1dStp 7 }

         dot1dStpMaxAge OBJECT-TYPE
             SYNTAX  Timeout
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The maximum age of Spanning Tree Protocol
                     information learned from the network on any port
                     before it is discarded, in units of hundredths of
                     a second.  This is the actual value that this
                     bridge is currently using."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.4"
             ::= { dot1dStp 8 }

         dot1dStpHelloTime OBJECT-TYPE
             SYNTAX  Timeout
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION



Decker, Langille, Rijsinghani & McCloghrie                     [Page 16]

RFC 1493                       Bridge MIB                      July 1993


                     "The amount of time between the transmission of
                     Configuration bridge PDUs by this node on any port
                     when it is the root of the spanning tree or trying
                     to become so, in units of hundredths of a second.
                     This is the actual value that this bridge is
                     currently using."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.5"
             ::= { dot1dStp 9 }

         dot1dStpHoldTime OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "This time value determines the interval length
                     during which no more than two Configuration bridge
                     PDUs shall be transmitted by this node, in units
                     of hundredths of a second."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.14"
             ::= { dot1dStp 10 }

         dot1dStpForwardDelay OBJECT-TYPE
             SYNTAX  Timeout
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "This time value, measured in units of hundredths
                     of a second, controls how fast a port changes its
                     spanning state when moving towards the Forwarding
                     state.  The value determines how long the port
                     stays in each of the Listening and Learning
                     states, which precede the Forwarding state.  This
                     value is also used, when a topology change has
                     been detected and is underway, to age all dynamic
                     entries in the Forwarding Database.  [Note that
                     this value is the one that this bridge is
                     currently using, in contrast to
                     dot1dStpBridgeForwardDelay which is the value that
                     this bridge and all others would start using
                     if/when this bridge were to become the root.]"
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.6"
             ::= { dot1dStp 11 }

         dot1dStpBridgeMaxAge OBJECT-TYPE
             SYNTAX  Timeout (600..4000)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 17]

RFC 1493                       Bridge MIB                      July 1993


             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The value that all bridges use for MaxAge when
                     this bridge is acting as the root.  Note that
                     802.1D-1990 specifies that the range for this
                     parameter is related to the value of
                     dot1dStpBridgeHelloTime. The granularity of this
                     timer is specified by 802.1D-1990 to be 1 second.
                     An agent may return a badValue error if a set is
                     attempted to a value which is not a whole number
                     of seconds."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.8"
             ::= { dot1dStp 12 }

         dot1dStpBridgeHelloTime OBJECT-TYPE
             SYNTAX  Timeout (100..1000)
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The value that all bridges use for HelloTime when
                     this bridge is acting as the root.  The
                     granularity of this timer is specified by 802.1D-
                     1990 to be 1 second.  An agent may return a
                     badValue error if a set is attempted to a value
                     which is not a whole number of seconds."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.9"
             ::= { dot1dStp 13 }

         dot1dStpBridgeForwardDelay OBJECT-TYPE
             SYNTAX  Timeout (400..3000)
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The value that all bridges use for ForwardDelay
                     when this bridge is acting as the root.  Note that
                     802.1D-1990 specifies that the range for this
                     parameter is related to the value of
                     dot1dStpBridgeMaxAge.  The granularity of this
                     timer is specified by 802.1D-1990 to be 1 second.
                     An agent may return a badValue error if a set is
                     attempted to a value which is not a whole number
                     of seconds."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.3.10"
             ::= { dot1dStp 14 }



Decker, Langille, Rijsinghani & McCloghrie                     [Page 18]

RFC 1493                       Bridge MIB                      July 1993


         -- The Spanning Tree Port Table

         dot1dStpPortTable OBJECT-TYPE
             SYNTAX  SEQUENCE OF Dot1dStpPortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A table that contains port-specific information
                     for the Spanning Tree Protocol."
             ::= { dot1dStp 15 }

         dot1dStpPortEntry OBJECT-TYPE
             SYNTAX  Dot1dStpPortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A list of information maintained by every port
                     about the Spanning Tree Protocol state for that
                     port."
             INDEX   { dot1dStpPort }
             ::= { dot1dStpPortTable 1 }

         Dot1dStpPortEntry ::=
             SEQUENCE {
                 dot1dStpPort
                     INTEGER,
                 dot1dStpPortPriority
                     INTEGER,
                 dot1dStpPortState
                     INTEGER,
                 dot1dStpPortEnable
                     INTEGER,
                 dot1dStpPortPathCost
                     INTEGER,
                 dot1dStpPortDesignatedRoot
                     BridgeId,
                 dot1dStpPortDesignatedCost
                     INTEGER,
                 dot1dStpPortDesignatedBridge
                     BridgeId,
                 dot1dStpPortDesignatedPort
                     OCTET STRING,
                 dot1dStpPortForwardTransitions
                     Counter
             }

         dot1dStpPort OBJECT-TYPE
             SYNTAX  INTEGER (1..65535)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 19]

RFC 1493                       Bridge MIB                      July 1993


             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The port number of the port for which this entry
                     contains Spanning Tree Protocol management
                     information."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.8.2.1.2"
             ::= { dot1dStpPortEntry 1 }

         dot1dStpPortPriority OBJECT-TYPE
             SYNTAX  INTEGER (0..255)
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The value of the priority field which is
                     contained in the first (in network byte order)
                     octet of the (2 octet long) Port ID.  The other
                     octet of the Port ID is given by the value of
                     dot1dStpPort."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.1"
             ::= { dot1dStpPortEntry 2 }

         dot1dStpPortState OBJECT-TYPE
             SYNTAX  INTEGER {
                         disabled(1),
                         blocking(2),
                         listening(3),
                         learning(4),
                         forwarding(5),
                         broken(6)
                     }
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The port's current state as defined by
                     application of the Spanning Tree Protocol.  This
                     state controls what action a port takes on
                     reception of a frame.  If the bridge has detected
                     a port that is malfunctioning it will place that
                     port into the broken(6) state.  For ports which
                     are disabled (see dot1dStpPortEnable), this object
                     will have a value of disabled(1)."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.2"
             ::= { dot1dStpPortEntry 3 }




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RFC 1493                       Bridge MIB                      July 1993


         dot1dStpPortEnable OBJECT-TYPE
             SYNTAX  INTEGER {
                         enabled(1),
                         disabled(2)
                     }
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The enabled/disabled status of the port."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.2"
             ::= { dot1dStpPortEntry 4 }

         dot1dStpPortPathCost OBJECT-TYPE
             SYNTAX  INTEGER (1..65535)
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The contribution of this port to the path cost of
                     paths towards the spanning tree root which include
                     this port.  802.1D-1990 recommends that the
                     default value of this parameter be in inverse
                     proportion to the speed of the attached LAN."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.3"
             ::= { dot1dStpPortEntry 5 }

         dot1dStpPortDesignatedRoot OBJECT-TYPE
             SYNTAX  BridgeId
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The unique Bridge Identifier of the Bridge
                     recorded as the Root in the Configuration BPDUs
                     transmitted by the Designated Bridge for the
                     segment to which the port is attached."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.4"
             ::= { dot1dStpPortEntry 6 }

         dot1dStpPortDesignatedCost OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The path cost of the Designated Port of the
                     segment connected to this port.  This value is
                     compared to the Root Path Cost field in received



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RFC 1493                       Bridge MIB                      July 1993


                     bridge PDUs."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.5"
             ::= { dot1dStpPortEntry 7 }

         dot1dStpPortDesignatedBridge OBJECT-TYPE
             SYNTAX  BridgeId
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The Bridge Identifier of the bridge which this
                     port considers to be the Designated Bridge for
                     this port's segment."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.6"
             ::= { dot1dStpPortEntry 8 }

         dot1dStpPortDesignatedPort OBJECT-TYPE
             SYNTAX  OCTET STRING (SIZE (2))
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The Port Identifier of the port on the Designated
                     Bridge for this port's segment."
             REFERENCE
                     "IEEE 802.1D-1990: Section 4.5.5.7"
             ::= { dot1dStpPortEntry 9 }

         dot1dStpPortForwardTransitions OBJECT-TYPE
             SYNTAX  Counter
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of times this port has transitioned
                     from the Learning state to the Forwarding state."
             ::= { dot1dStpPortEntry 10 }


         -- the dot1dTp group

         -- Implementation of the dot1dTp group is optional.  It is
         -- implemented by those bridges that support the transparent
         -- bridging mode.  A transparent or SRT bridge will implement
         -- this group.


         dot1dTpLearnedEntryDiscards OBJECT-TYPE
             SYNTAX  Counter



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RFC 1493                       Bridge MIB                      July 1993


             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The total number of Forwarding Database entries,
                     which have been or would have been learnt, but
                     have been discarded due to a lack of space to
                     store them in the Forwarding Database.  If this
                     counter is increasing, it indicates that the
                     Forwarding Database is regularly becoming full (a
                     condition which has unpleasant performance effects
                     on the subnetwork).  If this counter has a
                     significant value but is not presently increasing,
                     it indicates that the problem has been occurring
                     but is not persistent."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.7.1.1.3"
             ::= { dot1dTp 1 }

         dot1dTpAgingTime OBJECT-TYPE
             SYNTAX   INTEGER (10..1000000)
             ACCESS   read-write
             STATUS   mandatory
             DESCRIPTION
                     "The timeout period in seconds for aging out
                     dynamically learned forwarding information.
                     802.1D-1990 recommends a default of 300 seconds."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.7.1.1.3"
             ::= { dot1dTp 2 }


         --  The Forwarding Database for Transparent Bridges

         dot1dTpFdbTable OBJECT-TYPE
             SYNTAX  SEQUENCE OF Dot1dTpFdbEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A table that contains information about unicast
                     entries for which the bridge has forwarding and/or
                     filtering information.  This information is used
                     by the transparent bridging function in
                     determining how to propagate a received frame."
             ::= { dot1dTp 3 }

         dot1dTpFdbEntry OBJECT-TYPE
             SYNTAX  Dot1dTpFdbEntry
             ACCESS  not-accessible



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RFC 1493                       Bridge MIB                      July 1993


             STATUS  mandatory
             DESCRIPTION
                     "Information about a specific unicast MAC address
                     for which the bridge has some forwarding and/or
                     filtering information."
             INDEX   { dot1dTpFdbAddress }
             ::= { dot1dTpFdbTable 1 }

         Dot1dTpFdbEntry ::=
             SEQUENCE {
                 dot1dTpFdbAddress
                     MacAddress,
                 dot1dTpFdbPort
                     INTEGER,
                 dot1dTpFdbStatus
                     INTEGER
             }

         dot1dTpFdbAddress OBJECT-TYPE
             SYNTAX  MacAddress
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "A unicast MAC address for which the bridge has
                     forwarding and/or filtering information."
             REFERENCE
                     "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
             ::= { dot1dTpFdbEntry 1 }

         dot1dTpFdbPort OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "Either the value '0', or the port number of the
                     port on which a frame having a source address
                     equal to the value of the corresponding instance
                     of dot1dTpFdbAddress has been seen.  A value of
                     '0' indicates that the port number has not been
                     learned but that the bridge does have some
                     forwarding/filtering information about this
                     address (e.g. in the dot1dStaticTable).
                     Implementors are encouraged to assign the port
                     value to this object whenever it is learned even
                     for addresses for which the corresponding value of
                     dot1dTpFdbStatus is not learned(3)."
             ::= { dot1dTpFdbEntry 2 }




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RFC 1493                       Bridge MIB                      July 1993


         dot1dTpFdbStatus OBJECT-TYPE
             SYNTAX  INTEGER {
                         other(1),
                         invalid(2),
                         learned(3),
                         self(4),
                         mgmt(5)
                     }
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The status of this entry.  The meanings of the
                     values are:

                       other(1)   : none of the following.  This would
                                    include the case where some other
                                    MIB object (not the corresponding
                                    instance of dot1dTpFdbPort, nor an
                                    entry in the dot1dStaticTable) is
                                    being used to determine if and how
                                    frames addressed to the value of
                                    the corresponding instance of
                                    dot1dTpFdbAddress are being
                                    forwarded.

                       invalid(2) : this entry is not longer valid
                                    (e.g., it was learned but has since
                                    aged-out), but has not yet been
                                    flushed from the table.

                       learned(3) : the value of the corresponding
                                    instance of dot1dTpFdbPort was
                                    learned, and is being used.

                       self(4)    : the value of the corresponding
                                    instance of dot1dTpFdbAddress
                                    represents one of the bridge's
                                    addresses.  The corresponding
                                    instance of dot1dTpFdbPort
                                    indicates which of the bridge's
                                    ports has this address.

                       mgmt(5)    : the value of the corresponding
                                    instance of dot1dTpFdbAddress is
                                    also the value of an existing
                                    instance of dot1dStaticAddress."
             ::= { dot1dTpFdbEntry 3 }




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RFC 1493                       Bridge MIB                      July 1993


         --  Port Table for Transparent Bridges

         dot1dTpPortTable OBJECT-TYPE
             SYNTAX  SEQUENCE OF Dot1dTpPortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A table that contains information about every
                     port that is associated with this transparent
                     bridge."
             ::= { dot1dTp 4 }

         dot1dTpPortEntry OBJECT-TYPE
             SYNTAX  Dot1dTpPortEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A list of information for each port of a
                     transparent bridge."
             INDEX   { dot1dTpPort }
             ::= { dot1dTpPortTable 1 }

         Dot1dTpPortEntry ::=
             SEQUENCE {
                 dot1dTpPort
                     INTEGER,
                 dot1dTpPortMaxInfo
                     INTEGER,
                 dot1dTpPortInFrames
                     Counter,
                 dot1dTpPortOutFrames
                     Counter,
                 dot1dTpPortInDiscards
                     Counter
             }

         dot1dTpPort OBJECT-TYPE
             SYNTAX  INTEGER (1..65535)
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The port number of the port for which this entry
                     contains Transparent bridging management
                     information."
             ::= { dot1dTpPortEntry 1 }

         -- It would be nice if we could use ifMtu as the size of the
         -- largest INFO field, but we can't because ifMtu is defined



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RFC 1493                       Bridge MIB                      July 1993


         -- to be the size that the (inter-)network layer can use which
         -- can differ from the MAC layer (especially if several layers
         -- of encapsulation are used).

         dot1dTpPortMaxInfo OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The maximum size of the INFO (non-MAC) field that
                     this port will receive or transmit."
             ::= { dot1dTpPortEntry 2 }

         dot1dTpPortInFrames OBJECT-TYPE
             SYNTAX  Counter
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of frames that have been received by
                     this port from its segment. Note that a frame
                     received on the interface corresponding to this
                     port is only counted by this object if and only if
                     it is for a protocol being processed by the local
                     bridging function, including bridge management
                     frames."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.6.1.1.3"
             ::= { dot1dTpPortEntry 3 }

         dot1dTpPortOutFrames OBJECT-TYPE
             SYNTAX  Counter
             ACCESS  read-only
             STATUS  mandatory
             DESCRIPTION
                     "The number of frames that have been transmitted
                     by this port to its segment.  Note that a frame
                     transmitted on the interface corresponding to this
                     port is only counted by this object if and only if
                     it is for a protocol being processed by the local
                     bridging function, including bridge management
                     frames."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.6.1.1.3"
             ::= { dot1dTpPortEntry 4 }

         dot1dTpPortInDiscards OBJECT-TYPE
             SYNTAX   Counter
             ACCESS   read-only



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RFC 1493                       Bridge MIB                      July 1993


             STATUS   mandatory
             DESCRIPTION
                     "Count of valid frames received which were
                     discarded (i.e., filtered) by the Forwarding
                     Process."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.6.1.1.3"
             ::= { dot1dTpPortEntry 5 }


         -- The Static (Destination-Address Filtering) Database

         -- Implementation of this group is optional.


         dot1dStaticTable OBJECT-TYPE
             SYNTAX  SEQUENCE OF Dot1dStaticEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "A table containing filtering information
                     configured into the bridge by (local or network)
                     management specifying the set of ports to which
                     frames received from specific ports and containing
                     specific destination addresses are allowed to be
                     forwarded.  The value of zero in this table as the
                     port number from which frames with a specific
                     destination address are received, is used to
                     specify all ports for which there is no specific
                     entry in this table for that particular
                     destination address.  Entries are valid for
                     unicast and for group/broadcast addresses."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.7.2"
             ::= { dot1dStatic 1 }

         dot1dStaticEntry OBJECT-TYPE
             SYNTAX  Dot1dStaticEntry
             ACCESS  not-accessible
             STATUS  mandatory
             DESCRIPTION
                     "Filtering information configured into the bridge
                     by (local or network) management specifying the
                     set of ports to which frames received from a
                     specific port and containing a specific
                     destination address are allowed to be forwarded."
             REFERENCE
                     "IEEE 802.1D-1990: Section 6.7.2"



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RFC 1493                       Bridge MIB                      July 1993


             INDEX   { dot1dStaticAddress, dot1dStaticReceivePort }
             ::= { dot1dStaticTable 1 }

         Dot1dStaticEntry ::=
             SEQUENCE {
                 dot1dStaticAddress
                     MacAddress,
                 dot1dStaticReceivePort
                     INTEGER,
                 dot1dStaticAllowedToGoTo
                     OCTET STRING,
                 dot1dStaticStatus
                     INTEGER
             }

         dot1dStaticAddress OBJECT-TYPE
             SYNTAX  MacAddress
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The destination MAC address in a frame to which
                     this entry's filtering information applies.  This
                     object can take the value of a unicast address, a
                     group address or the broadcast address."
             REFERENCE
                     "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
             ::= { dot1dStaticEntry 1 }

         dot1dStaticReceivePort OBJECT-TYPE
             SYNTAX  INTEGER
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "Either the value '0', or the port number of the
                     port from which a frame must be received in order
                     for this entry's filtering information to apply.
                     A value of zero indicates that this entry applies
                     on all ports of the bridge for which there is no
                     other applicable entry."
             ::= { dot1dStaticEntry 2 }

         dot1dStaticAllowedToGoTo OBJECT-TYPE
             SYNTAX  OCTET STRING
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "The set of ports to which frames received from a
                     specific port and destined for a specific MAC



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RFC 1493                       Bridge MIB                      July 1993


                     address, are allowed to be forwarded.  Each octet
                     within the value of this object specifies a set of
                     eight ports, with the first octet specifying ports
                     1 through 8, the second octet specifying ports 9
                     through 16, etc.  Within each octet, the most
                     significant bit represents the lowest numbered
                     port, and the least significant bit represents the
                     highest numbered port.  Thus, each port of the
                     bridge is represented by a single bit within the
                     value of this object.  If that bit has a value of
                     '1' then that port is included in the set of
                     ports; the port is not included if its bit has a
                     value of '0'.  (Note that the setting of the bit
                     corresponding to the port from which a frame is
                     received is irrelevant.)  The default value of
                     this object is a string of ones of appropriate
                     length."
             ::= { dot1dStaticEntry 3 }

         dot1dStaticStatus OBJECT-TYPE
             SYNTAX  INTEGER {
                         other(1),
                         invalid(2),
                         permanent(3),
                         deleteOnReset(4),
                         deleteOnTimeout(5)
                     }
             ACCESS  read-write
             STATUS  mandatory
             DESCRIPTION
                     "This object indicates the status of this entry.
                     The default value is permanent(3).

                          other(1) - this entry is currently in use but
                               the conditions under which it will
                               remain so are different from each of the
                               following values.
                          invalid(2) - writing this value to the object
                               removes the corresponding entry.
                          permanent(3) - this entry is currently in use
                               and will remain so after the next reset
                               of the bridge.
                          deleteOnReset(4) - this entry is currently in
                               use and will remain so until the next
                               reset of the bridge.
                          deleteOnTimeout(5) - this entry is currently
                               in use and will remain so until it is
                               aged out."



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RFC 1493                       Bridge MIB                      July 1993


             ::= { dot1dStaticEntry 4 }


         -- Traps for use by Bridges

         -- Traps for the Spanning Tree Protocol

         newRoot TRAP-TYPE
             ENTERPRISE  dot1dBridge
             DESCRIPTION
                     "The newRoot trap indicates that the sending agent
                     has become the new root of the Spanning Tree; the
                     trap is sent by a bridge soon after its election
                     as the new root, e.g., upon expiration of the
                     Topology Change Timer immediately subsequent to
                     its election.  Implementation of this trap is
                     optional."
             ::= 1

         topologyChange TRAP-TYPE
             ENTERPRISE  dot1dBridge
             DESCRIPTION
                     "A topologyChange trap is sent by a bridge when
                     any of its configured ports transitions from the
                     Learning state to the Forwarding state, or from
                     the Forwarding state to the Blocking state.  The
                     trap is not sent if a newRoot trap is sent for the
                     same transition.  Implementation of this trap is
                     optional."
             ::= 2

         END

6.  Acknowledgments

  This document was produced on behalf of the Bridge Sub-Working Group
  of the SNMP Working Group of the Internet Engineering Task Force.
  Over the course of its deliberations, the working group received four
  separate documents for consideration as the basis for its work.  The
  first was submitted by Stan Froyd of Advanced Computer
  Communications; the second by Richard Fox of SynOptics; the third by
  Eric Decker of cisco Inc. and Keith McCloghrie of Hughes LAN Systems;
  and the fourth by Paul Langille and Anil Rijsinghani of Digital
  Equipment Corp. After considering the submissions, the working group
  chose to proceed with a document formed as a conjunction of the
  latter two submissions.  This document is the result.





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RFC 1493                       Bridge MIB                      July 1993


  The authors wish to thank the members of the Bridge Working Group for
  their many comments and suggestions which improved this effort. In
  particular, Fred Baker (chairman of the working group) of ACC, Steve
  Sherry of Xyplex, and Frank Kastenholz of Clearpoint Research Corp.
  Others members of the Bridge Working Group who contributed to this
  effort are:

              Bill Anderson, Mitre
              Karl Auerbach, Epilogue
              Fred Baker, ACC (chair)
              Terry Bradley, Wellfleet
              Ted Brunner, Bellcore
              Jeffrey Buffum, Apollo
              Chris ChioTasso, Fibronics
              Anthony Chung, HLS
              Chuck Davin, MIT-LCS
              Andy Davis, Spider
              Eric Decker, cisco
              Nadya El-Afandi, Network Systems
              Gary Ellis,HP/Apollo
              Richard Fox, SynOptics
              Stan Froyd, ACC
              Frank Kastenholz, Clearpoint Research
              Shirnshon Kaufman,
              Jim Kinder, Fibercom
              Cheryl Krupczak,NCR
              Paul Langille, Digital
              Peter Lin,Vitalink
              Keith McCloghrie, HLS
              Donna McMaster, SynOptics
              Dave Perkins, 3Com
              Jim Reinstedler, Ungermann Bass
              Anil Rijsinghani, Digital
              Mark Schaefer, David Systems
              Steve Sherry, Xyplex
              Bob Stewart, Xyplex
              Emil Sturniolo,
              Kevin Synott, Retix
              Ian Thomas, Chipcom
              Maurice Turcott, Racal
              Fei Xu,










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RFC 1493                       Bridge MIB                      July 1993


7.  References

  [1] Cerf, V., "IAB Recommendations for the Development of Internet
      Network Management Standards", RFC 1052, NRI, April 1988.

  [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
      Group", RFC 1109, NRI, August 1989.

  [3] Rose M., and K. McCloghrie, "Structure and Identification of
      Management Information for TCP/IP-based internets", STD 16, RFC
      1155, Performance Systems International, Hughes LAN Systems, May
      1990.

  [4] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
      Network Management Protocol", STD 15, RFC 1157, SNMP Research,
      Performance Systems International, Performance Systems
      International, MIT Laboratory for Computer Science, May 1990.

  [5] McCloghrie K., and M. Rose, Editors, "Management Information Base
      for Network Management of TCP/IP-based internets", STD 17, RFC
      1213, Performance Systems International, March 1991.

  [6] Information processing systems - Open Systems Interconnection -
      Specification of Abstract Syntax Notation One (ASN.1),
      International Organization for Standardization, International
      Standard 8824, December 1987.

  [7] Information processing systems - Open Systems Interconnection -
      Specification of Basic Encoding Rules for Abstract Notation One
      (ASN.1), International Organization for Standardization,
      International Standard 8825, December 1987.

  [8] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
      STD 16, RFC 1212, Performance Systems International, Hughes LAN
      Systems, March 1991.

  [9] Rose, M., Editor, "A Convention for Defining Traps for use with
      the SNMP", RFC 1215, Performance Systems International, March
      1991.

 [10] ANSI/IEEE Standard 802.1D-1990 MAC Bridges, IEEE Project 802
      Local and Metropolitan Area Networks, (March 8, 1991).

 [11] ISO DIS 10038 MAC Bridges.

8.  Security Considerations

  Security issues are not discussed in this memo.



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RFC 1493                       Bridge MIB                      July 1993


9.  Authors' Addresses

  Eric B. Decker
  cisco Systems, Inc.
  1525 O'Brien Dr.
  Menlo Park, CA  94025

  Phone: (415) 326-1941
  Email: [email protected]


  Paul Langille
  Digital Equipment Corporation
  Digital Drive, MK02-2/K03
  Merrimack, NH 03054

  Phone: (603) 884-4045
  EMail: [email protected]


  Anil Rijsinghani
  Digital Equipment Corporation
  550 King Street
  Littleton, MA 01460

  Phone: (508) 486-6786
  EMail: [email protected]


  Keith McCloghrie
  Hughes LAN Systems, Inc.
  1225 Charleston Road
  Mountain View, CA 94043

  Phone: (415) 966-7934
  EMail: [email protected]















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